linux/drivers/mtd
Zhihao Cheng f9e109a209 mtd: mtdconcat: Judge callback existence based on the master
Since commit 46b5889cc2c5("mtd: implement proper partition handling")
applied, mtd partition device won't hold some callback functions, such
as _block_isbad, _block_markbad, etc. Besides, function mtd_block_isbad()
will get mtd device's master mtd device, then invokes master mtd device's
callback function. So, following process may result mtd_block_isbad()
always return 0, even though mtd device has bad blocks:

1. Split a mtd device into 3 partitions: PA, PB, PC
[ Each mtd partition device won't has callback function _block_isbad(). ]
2. Concatenate PA and PB as a new mtd device PN
[ mtd_concat_create() finds out each subdev has no callback function
_block_isbad(), so PN won't be assigned callback function
concat_block_isbad(). ]
Then, mtd_block_isbad() checks "!master->_block_isbad" is true, will
always return 0.

Reproducer:
// reproduce.c
static int __init init_diy_module(void)
{
	struct mtd_info *mtd[2];
	struct mtd_info *mtd_combine = NULL;

	mtd[0] = get_mtd_device_nm("NAND simulator partition 0");
	if (!mtd[0]) {
		pr_err("cannot find mtd1\n");
		return -EINVAL;
	}
	mtd[1] = get_mtd_device_nm("NAND simulator partition 1");
	if (!mtd[1]) {
		pr_err("cannot find mtd2\n");
		return -EINVAL;
	}

	put_mtd_device(mtd[0]);
	put_mtd_device(mtd[1]);

	mtd_combine = mtd_concat_create(mtd, 2, "Combine mtd");
	if (mtd_combine == NULL) {
		pr_err("combine failed\n");
		return -EINVAL;
	}

	mtd_device_register(mtd_combine, NULL, 0);
	pr_info("Combine success\n");

	return 0;
}

1. ID="0x20,0xac,0x00,0x15"
2. modprobe nandsim id_bytes=$ID parts=50,100 badblocks=100
3. insmod reproduce.ko
4. flash_erase /dev/mtd3 0 0
  libmtd: error!: MEMERASE64 ioctl failed for eraseblock 100 (mtd3)
  error 5 (Input/output error)
  // Should be "flash_erase: Skipping bad block at 00c80000"

Fixes: 46b5889cc2 ("mtd: implement proper partition handling")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210817114857.2784825-2-chengzhihao1@huawei.com
2021-08-17 18:43:30 +02:00
..
chips mtd: Convert list_for_each to entry variant 2021-06-11 21:05:06 +02:00
devices mtd: devices: add support for microchip 48l640 EERAM 2021-06-11 20:43:12 +02:00
hyperbus mtd: hyperbus: Fix build failure when only RPCIF_HYPERBUS is enabled 2020-10-12 21:12:08 +02:00
lpddr mtd: lpddr: fix excessive stack usage with clang 2020-08-27 14:36:07 +02:00
maps mtd: maps: remove dead MTD map driver for PMC-Sierra MSP boards 2021-08-17 18:43:28 +02:00
nand MTD core changes: 2021-07-05 11:21:51 -07:00
parsers MTD core changes: 2021-07-05 11:21:51 -07:00
spi-nor mtd: spi-nor: remove redundant continue statement 2021-06-21 11:17:10 +05:30
tests mtd: tests: Remove redundant assignment to err 2021-05-10 12:48:35 +02:00
ubi This pull request contains the following changes for UBIFS: 2021-07-09 10:10:47 -07:00
ftl.c mtd: ftl: Use module_mtd_blktrans to register driver 2021-03-11 09:37:48 +01:00
inftlcore.c mtd: inftlcore: Use module_mtd_blktrans to register driver 2021-03-11 09:37:48 +01:00
inftlmount.c mtd: inftl: remove unnecessary oom message 2021-06-11 20:44:21 +02:00
Kconfig mtdblock: Add comment about UBI block devices 2021-08-06 22:05:13 +02:00
Makefile mtd: Support kmsg dumper based on pstore/blk 2020-05-31 19:49:01 -07:00
mtd_blkdevs.c mtd_blkdevs: initialze new->rq in add_mtd_blktrans_dev 2021-06-16 06:53:50 -06:00
mtdblock_ro.c mtdblock: Warn if added for a NAND device 2021-08-17 18:41:59 +02:00
mtdblock.c mtdblock: Warn if added for a NAND device 2021-08-17 18:41:59 +02:00
mtdchar.c mtd: add OTP (one-time-programmable) erase ioctl 2021-03-28 19:24:54 +02:00
mtdconcat.c mtd: mtdconcat: Judge callback existence based on the master 2021-08-17 18:43:30 +02:00
mtdcore.c mtd: core: use MTD_DEVICE_ATTR_RO/RW() helper macros 2021-06-11 20:42:57 +02:00
mtdcore.h
mtdoops.c mtd: mtdoops: remove unnecessary oom message 2021-06-11 20:43:46 +02:00
mtdpart.c mtd: mtdpart: use DEVICE_ATTR_RO() helper macro 2021-06-11 20:42:45 +02:00
mtdpstore.c pstore/blk: Include zone in pstore_device_info 2021-06-16 21:09:31 -07:00
mtdsuper.c block: remove i_bdev 2020-12-01 14:53:39 -07:00
mtdswap.c mtd: mtdswap: Use module_mtd_blktrans to register driver 2021-03-11 09:37:48 +01:00
nftlcore.c mtd: nftlcore: remove set but rewrite variables 2021-05-10 12:11:46 +02:00
nftlmount.c mtd: nftl: remove unnecessary oom message 2021-06-11 20:43:26 +02:00
rfd_ftl.c mtd: rfd_ftl: use container_of() rather than cast 2021-08-17 18:42:58 +02:00
sm_ftl.c drivers: mtd: sm_ftl: Fix alignment of block comment 2021-05-10 12:49:00 +02:00
sm_ftl.h
ssfdc.c